Heat dissipation device

ABSTRACT

A heat dissipation device used for dissipating heat from an electronic device mounted on a printed circuit board (PCB), includes a heat sink contacting with the electronic device, a locking device mounted on the heat sink and securing the heat sink onto the PCB. The locking device comprises a supporting plate extending through the heat sink, two arms respectively and slidably fixed on two opposite ends of the supporting plate and two fastening devices respectively slidably fixed to the two arms. The two arms can move along a first direction about the heat sink, and the two fastening devices can move along a second direction about the arms, thereby aligning the two fastening devices with two through holes defined in the printed circuit board, respectively.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device compatible with differently-configured printed circuit boards.

2. Description of Related Art

With development in computer technology, electronic devices operate at high speed. It is well known that higher speed the electronic devices operate at, more heat they generate. If the heat is not dissipated duly, the stability of the operation of the electronic devices will be impacted severely. Generally, in order to ensure the electronic device to run normally, a heat sink is used to dissipate the heat generated by the electronic device.

Conventionally, in order to keep the heat sink intimately contacting with the electronic device mounted on a printed circuit board (PCB), a securing mechanism is utilized to secure the heat sink to the PCB. The heat sink generally has a fixing bracket mounted on a bottom thereof. The fixing bracket defines a plurality of through holes at corners thereof. A plurality of retaining pillars each having a threaded hole defined therein, is provided at the PCB, surrounding the electronic device. The plurality of through holes of the fixing bracket is in alignment with the threaded holes of the retaining pillars, respectively. In assembly, a plurality of screws extends through the through holes of the fixing bracket and further engages in the threaded holes of the retaining pillars of the PCB, respectively, thereby securing the heat sink to the PCB. However, the heat sink is only compatible with the PCB with the threaded holes completely in alignment with the through holes of the fixing bracket of the heat sink. When a PCB having a layout of threaded holes different from that of the above-mentioned PCB due to different standards, is used, the pillars on the printed circuit board cannot be aligned with the through holes of the heat sink any more, and an engagement of the heat sink on the printed circuit board becomes impossible.

What is needed, therefore, is a heat dissipation device which can overcome the above disadvantages.

SUMMARY OF THE INVENTION

A heat dissipation device used for dissipating heat from an electronic device mounted on a printed circuit board (PCB), includes a heat sink contacting with the electronic device, a locking device mounted on the heat sink and securing the heat sink onto the PCB. The locking device comprises a supporting plate extending through the heat sink, two arms respectively fixed on two opposite ends of the supporting plate and two fastening devices respectively mounted at the two arms. The two arms can move along a first direction about the heat sink, and the two fastening devices can move along a second direction about the arms which is perpendicular to the first direction. Since the arms and the fastening devices are all movable with respect to the heat sink, the fastening devices can be adjusted to be accurately locked into through holes in the printed circuit board, and accordingly, the locking device is able to be suitable for printed circuit boards with different layouts.

Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an assembled view of a heat dissipation device in accordance with an embodiment of the present invention, with a printed circuit board located therebelow.

FIG. 2 is an exploded view of the heat dissipation device of FIG. 1.

FIG. 3 is an enlarged view of a heat sink and a locking device of the heat dissipation device of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a heat dissipation device in accordance with an embodiment of the present invention is used for dissipating heat from an electronic device 52 mounted on a printed circuit board (PCB) 50. The heat dissipation device includes a heat sink 10 contacting with the electronic device 52, a locking device 20 mounted on the heat sink 10 and securing the heat sink 10 onto the PCB 50, a fan 30, and a fixture 40 connecting the fan 30 with the heat sink 10.

Also referring to FIG. 2, the heat sink 10 includes a plurality of fins 12 connected together and a heat pipe 14 extending through the fins 12. Each fin 12 is made of a metal having a high heat conductivity, such as aluminum or copper. The heat pipe 14 is U-shaped and has an evaporating section 142 and a condensing section 144. The evaporating section 142 of the heat pipe 14 is inserted into a center of a bottom of the fins 12 and has a bottom surface coplanar with that of the fins 12. The condensing section 144 of the heat pipe 14 is inserted into an upper part of the fins 12. Two annular flanges 124 are extended horizontally from two opposite ends of an upper part of each fin 12 to define two threaded holes 120 surrounded by the two annular flanges 124, respectively. The fins 12 cooperatively define a channel 122 located above the evaporating section of the heat pipe 14.

Also referring to FIG. 3, the locking device 20 is used for securing the heat sink 10 to the PCB 50. The locking device 20 includes a rectangular supporting plate 22, two arms 24 respectively secured to two ends of the supporting plate 22 by two screws 26, and two fastening devices 28 respectively and engagingly retained in the two arms 24 for engaging in two through holes 54 in the PCB 50. The supporting plate 22 can extend through the channel 122 of the heat sink 10 and expose the two ends thereof out of two lateral sides of the heat sink 10. The two ends of the supporting plate 22 each define a threaded hole 220. Each of the two arms 24 is integrally formed of a metal plate and includes a first mounting portion 242, a second mounting portion 244 and a connecting portion 246 extending slantwise and downwardly from one end of the first mounting portion 242 to connect one side of the second mounting portion 244. The first mounting portion 242 and the second mounting portion 244 are perpendicular to each other, whereby the arm 24 has a T-shaped projection at a horizontal plane. The first mounting portion 242 defines an elongated through hole 2420 therein, which extends a length substantially the same as that of the first mounting portion 242. The elongated through holes 2420 are positioned to be aligned with the threaded holes 220 of the supporting plate 22. The screws 26 can extend through the elongated through holes 2420 of the first mounting portions 242 and threadedly engage with the threaded holes 220 of the supporting plate 22 to fix the first mounting portions 242 on the two ends of the supporting plate 22. Since the elongated through hole 2420 has a relatively large length, the screw 26 can freely move within the first mounting portion 242 along the length of the elongated through hole 2420, whereby the position of each arm 24 along a first direction, i.e., a front-to-rear direction of the heat sink 10 is adjustable. The second mounting portion 244 has an elongated through hole 2440 therein, which has a length substantially the same as that of the second mounting portion 244. The elongated through holes 2440 are positioned to be aligned with the through holes 54 in the PCB 50. The fastening devices 28 can extend through the elongated through holes 2440 of the second mounting portions 244 and engage in the through holes 54 in the PCB 50, to mount the second mounting portions 244 to the PCB 50. Like the screws 26, each fastening device 28 is also capable of freely moving within the second mounting portion 244 along the elongated through hole 2440, thereby adjusting the position thereof along a second direction, i.e., a lateral direction of the heat sink 10. The two fastening devices 28 each include a body and a spring 288 encircling the body. The body is integrally made of plastic and includes a head 282, a shaft 284 extending downwardly from a center of the head 282 and a wedge-shaped and elastic retaining block 286 formed at a distal end of the shaft 284. The two screws 26 each include a head 262 and a threaded shaft 264 extending downwardly from a center of the head 262.

The fixture 40 is used for fixing the fan 30 on the heat sink 10 and includes a main body 42 and two mounting plates 44 extending perpendicularly and downwardly from two lateral edges of the main body 42. The main body 42 defines a circular inlet 400 in a center thereof for allowing an airflow generated by the fan 30 therethrough. The main body 42 defines four threaded holes 420 at four corners thereof around the inlet 400, corresponding to four through holes 300 of the fan 30. Four screws 36 extend through the through holes 300 of the fan 30 and threadedly engage in the four threaded holes 420 of the main body 42 to attach the fan 30 to the fixture 40. The two mounting plates 44 each define two through holes 440 at two ends thereof corresponding to the two threaded holes 120 of the heat sink 10. Four screws 46 extend through the through holes 440 of the two mounting plates 44 and threadedly engage in the threaded holes 120 of the flanges 124 of the heat sink 10 to attach the fixture 40 to the heat sink 10.

The fan 30 is attached to a top surface of the fixture 40 and includes an upper flange 32 and a lower flange 34. The four through holes 300 are defined in each of the upper flange 32 and the lower flange 34. The screws 36 extend through the through holes 300 in the lower flange 34.

In assembly, the fan 30 is attached to the fixture 40 by the four screws 36; and the fixture 40 is then attached to the heat sink 10 by the four screws 46. The supporting plate 22 is brought to extend through the channel 122 of the heat sink 10 with the two ends thereof extending out of the two lateral sides of the heat sink 10. The screws 26 are brought to extend through the elongated through holes 2420 of the first mounting portions 242 and are driven to threadedly engage in the threaded holes 220 of the supporting plate 22. Before the first mounting portions 242 are firmly fixed on the two ends of the supporting plate 22, the first mounting portions 242 can move along the front-to-rear direction by moving the elongated through holes 2420 relative to the screws 26, to adjust the positions of the elongated through holes 2440 of the second mounting portions 244 until they are in alignment with the through holes 54 of the PCB 50. Then, the two screws 26 are screwed tightly into the threaded holes 220. Thereafter, the two fastening devices 28, which have been already inserted into the elongated through holes 2440 in a manner that the springs 288 are compressed between the heads 282 and the second mounting portions 244, are brought to slide within the elongated through holes 2440 so as to be aligned with the two through holes 54 in the PCB 50, respectively. The fastening devices 28 are pushed downwardly toward the through holes 54 in the PCB 50 by depressing the heads 282 of the fastening devices 28. The springs 288 are further depressed by the heads 282 of the fastening devices 28 toward the PCB 50, exerting downward pressing forces on top faces of the second mounting portions 244. Meanwhile, the retaining blocks 286 of the fastening devices 28 are inserted into the through holes 54 in the PCB 50 to engage with a bottom face of the PCB 50, thereby locking the fastening devices 28 to the PCB 50. Thus, the heat dissipation device is secured to the PCB 50, and the heat sink 10 has an intimate contact with the electronic device 52.

Due to the adjustable design of the fastening devices 28, the heat dissipation device can be compatible with PCBs having different layouts, thereby increasing the flexibility of the locking device 20.

It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A heat dissipation device for dissipating heat generated by an electronic device mounted on a printed circuit board, the heat dissipation device comprising: a heat sink; and a locking device for mounting the heat sink on the printed circuit board, the locking device comprising two arms respectively slidably mounted at two opposite lateral sides of the heat sink and two fastening devices respectively slidably mounted to the two arms, wherein the two arms can move on the heat sink along a first direction, and the two fastening devices can move on the arms along a second direction different from the first direction.
 2. The heat dissipation device as claimed in claim 1, wherein the first direction is perpendicular to the second direction.
 3. The heat dissipation device as claimed in claim 1, wherein the locking device further comprises a supporting plate attached to the heat sink, two ends of the supporting plate being respectively located out of the two opposite lateral sides of the heat sink and respectively connecting the two arms.
 4. The heat dissipation device as claimed in claim 3, wherein each of the two arms comprises a first mounting portion fixed on a corresponding one of the two ends of the supporting plate and a second mounting portion, the two fastening devices being respectively inserted thought the second mounting portions of the arms.
 5. The heat dissipation device as claimed in claim 4, wherein the first mounting portion and the second mounting portion respectively define an elongate first through hole and an elongate second through hole, and the elongate first holes of the two arms can move over the supporting plate, and the two fastening devices can move along the second elongate through holes of the two arms.
 6. The heat dissipation device as claimed in claim 5, wherein the two ends of the supporting plate each define a threaded hole, a screw extending through the elongate first through hole of the first mounting portion and engaging in the threaded hole of the supporting plate.
 7. The heat dissipation device as claimed in claim 4, wherein the first mounting portion and second mounting portion are perpendicular to each other, the two arms each further comprising a connecting portion interconnecting the first mounting portion and the second mounting portion.
 8. The heat dissipation device as claimed in claim 7, wherein the first mounting portion and the second mounting portion are respectively located at two adjacent sides of the heat sink.
 9. The heat dissipation device as claimed in claim 8, wherein the connecting portion extends slantwise and downwardly from the first mounting portion to connect with the second mounting portion.
 10. The heat dissipation device as claimed in claim 4, wherein the two fastening devices each comprise a head, a shaft extending downwardly from the head, a retaining portion formed at a distal end of the shaft and a spring encircling the shaft, the spring being compressed between the head and a top surface of the second mounting portion, the shaft extending through the second mounting portion.
 11. The heat dissipation device as claimed in claim 3, wherein the heat sink comprises a plurality of fins connected together, and the first direction is parallel to the plurality of fins.
 12. The heat dissipation device as claimed in claim 11, wherein the plurality of fins defines a channel along the second direction, the supporting plate being inserted into the channel in the plurality of fins, a fan being mounted on a top of the heat sink.
 13. The heat dissipation device as claimed in claim 11, wherein the heat sink further comprises a heat pipe which comprises an evaporating section and a condensing section, the evaporating section being inserted into a center of a bottom of the plurality of fins and having a bottom surface coplanar with that of the plurality of fins, the condensing section being inserted into the plurality of fins and located above the evaporating section.
 14. A heat dissipation device comprising: a heat sink; and a locking device for mounting the heat sink on a printed circuit board, comprising an arm movably attached to the heat sink and a fastening device movably attached to the arm, wherein the arm and the fastening device are movable along different directions to align the fastening device with a selected part of the printed circuit board, whereby the fastening device can be accurately secured with the selected part of the printed circuit board.
 15. The heat dissipation device as claimed in claim 14, wherein the arm is movable along a first direction perpendicular to a second direction along which the fastening device is movable.
 16. The heat dissipation device as claimed in claim 14, wherein the arm comprises a first mounting portion slidably mounted to the heat sink and a second mounting portion to which the fastening device is slidably attached.
 17. The heat dissipation device as claimed in claim 16, wherein the second mounting portion is located at a level lower than that where the first mounting portion is located.
 18. The heat dissipation device as claimed in claim 15, wherein the locking device further comprises a plate horizontally extending through the heat sink along the second direction, the arm being attached to an end of the plate which extends beyond the heat sink. 